2 ; Graphics driver for the 640x200x2 mode on the C128 VDC
3 ; Maciej 'YTM/Elysium' Witkowiak <ytm@elysium.pl>
5 ; 2004-04-04, Greg King
8 ; For any smart monkey that will try to optimize this: PLEASE do tests on
9 ; real VDC, not only VICE.
11 ; Only DONE routine contains C128-mode specific stuff, everything else will
12 ; work in C64-mode of C128 (C64 needs full VDC init then).
14 ; With special initialization and CALC we can get 320x200 double-pixel mode.
16 ; Color translation values for BROWN and GRAY3 are obviously wrong, they
17 ; could be replaced by equiv. of ORANGE and GRAY2 but this would give only
18 ; 14 of 16 colors available.
20 ; Register 25 ($19) is said to require different value for VDC v1, but I
21 ; couldn't find what it should be.
23 .include "zeropage.inc"
25 .include "tgi-kernel.inc"
26 .include "tgi-mode.inc"
27 .include "tgi-error.inc"
32 ; ------------------------------------------------------------------------
35 VDC_ADDR_REG = $D600 ; VDC address
36 VDC_DATA_REG = $D601 ; VDC data
38 VDC_DSP_HI = 12 ; registers used
49 ; ------------------------------------------------------------------------
50 ; Header. Includes jump table and constants.
54 ; First part of the header is a structure that has a magic and defines the
55 ; capabilities of the driver
57 .byte $74, $67, $69 ; "tgi"
58 .byte TGI_API_VERSION ; TGI API version number
59 xres: .word 640 ; X resolution
60 yres: .word 200 ; Y resolution
61 .byte 2 ; Number of drawing colors
62 pages: .byte 1 ; Number of screens available
63 .byte 8 ; System font X size
64 .byte 8 ; System font Y size
65 .res 4, $00 ; Reserved for future extensions
67 ; Next comes the jump table. Currently all entries must be valid and may point
68 ; to an RTS for test versions (function not implemented).
90 .addr 0 ; IRQ entry is unused
92 ; ------------------------------------------------------------------------
95 ; Variables mapped to the zero page segment variables. Some of these are
96 ; used for passing parameters to the driver.
104 ADDR = tmp1 ; (2) CALC
105 TEMP = tmp3 ; CALC icmp
108 TEMP4 = sreg+1 ; LINE
110 ; Line routine stuff (must be on zpage)
113 ERR = regsave ; (2) LINE
114 NX = regsave+2 ; (2) LINE
116 XX = ptr3 ; (2) CIRCLE
117 YY = ptr4 ; (2) CIRCLE
118 MaxO = sreg ; (overwritten by TEMP3+TEMP4, but restored from OG/OU anyway)
119 XS = regsave ; (2) CIRCLE
120 YS = regsave+2 ; (2) CIRCLE
122 ; Absolute variables used in the code
126 SCRBASE: .res 1 ; High byte of screen base
128 ERROR: .res 1 ; Error code
129 PALETTE: .res 2 ; The current palette
131 BITMASK: .res 1 ; $00 = clear, $FF = set pixels
133 OLDCOLOR: .res 1 ; colors before entering gfx mode
135 ; Line routine stuff (combined with CIRCLE to save space)
151 ; Constants and tables
155 DEFPALETTE: .byte $00, $0f ; White on black
156 PALETTESIZE = * - DEFPALETTE
158 BITTAB: .byte $80,$40,$20,$10,$08,$04,$02,$01
160 BITMASKL: .byte %11111111, %01111111, %00111111, %00011111
161 .byte %00001111, %00000111, %00000011, %00000001
163 BITMASKR: .byte %10000000, %11000000, %11100000, %11110000
164 .byte %11111000, %11111100, %11111110, %11111111
166 ; color translation table (indexed by VIC color)
167 COLTRANS: .byte $00, $0f, $08, $06, $0a, $04, $02, $0c
168 .byte $0d, $0b, $09, $01, $0e, $05, $03, $07
169 ; colors BROWN and GRAY3 are wrong
171 ; VDC initialization table (reg),(val),...,$ff
173 .byte VDC_DSP_HI, 0 ; viewpage 0 as default
175 .byte VDC_HSCROLL, $87
178 SCN80CLR: .byte 27,88,147,27,88,0
182 ; ------------------------------------------------------------------------
183 ; INSTALL routine. Is called after the driver is loaded into memory. May
184 ; initialize anything that has to be done just once. Is probably empty
187 ; Must set an error code: NO
191 ; check for VDC version and update register $19 value
193 ; check for VDC ram size and update number of available screens
195 ldx #VDC_CSET ; determine size of RAM...
199 jsr VDCWriteReg ; turn on 64k
201 jsr settestadr1 ; save original value of test byte
205 lda #$55 ; write $55 here
207 jsr test64k ; read it here and there
208 lda #$aa ; write $aa here
210 jsr test64k ; read it here and there
214 jsr VDCWriteByte ; restore original value of test byte
216 lda ptr1 ; do bytes match?
225 jsr VDCWriteReg ; restore 16/64k flag
226 jmp @endok ; and leave default values for 16k
233 sta SCRBASE ; draw page 0 as default
243 jsr VDCWriteByte ; write $55
245 jsr VDCReadByte ; read here
248 jsr VDCReadByte ; and there
257 ldy #$02 ; test page 2 (here)
260 ldy #$42 ; or page 64+2 (there)
264 ; ------------------------------------------------------------------------
265 ; UNINSTALL routine. Is called before the driver is removed from memory. May
266 ; clean up anything done by INSTALL but is probably empty most of the time.
268 ; Must set an error code: NO
275 ; ------------------------------------------------------------------------
276 ; INIT: Changes an already installed device from text mode to graphics
278 ; Note that INIT/DONE may be called multiple times while the driver
279 ; is loaded, while INSTALL is only called once, so any code that is needed
280 ; to initializes variables and so on must go here. Setting palette and
281 ; clearing the screen is not needed because this is called by the graphics
283 ; The graphics kernel will never call INIT when a graphics mode is already
284 ; active, so there is no need to protect against that.
286 ; Must set an error code: YES
291 ; Initialize variables
296 ; Remeber current color value
301 ; Switch into graphics mode (set view page 0)
304 @L2: ldx InitVDCTab,y
313 ; Done, reset the error code
319 ; ------------------------------------------------------------------------
320 ; DONE: Will be called to switch the graphics device back into text mode.
321 ; The graphics kernel will never call DONE when no graphics mode is active,
322 ; so there is no need to protect against that.
324 ; Must set an error code: NO
328 ; This part is C128-mode specific
329 jsr $e179 ; reload character set and setup VDC
331 lda $d7 ; in 80-columns?
335 jsr $ffd2 ; print \xe,clr,\xe
339 jsr $ffd2 ; print clr
340 @L1: lda #0 ; restore view page
345 jsr VDCWriteReg ; restore color (background)
348 jmp VDCWriteReg ; switch to text screen
350 ; ------------------------------------------------------------------------
351 ; GETERROR: Return the error code in A and clear it.
359 ; ------------------------------------------------------------------------
360 ; CONTROL: Platform/driver specific entry point.
362 ; Must set an error code: YES
366 lda #TGI_ERR_INV_FUNC
370 ; ------------------------------------------------------------------------
371 ; CLEAR: Clears the screen.
373 ; Must set an error code: NO
382 jsr VDCWriteReg ; set fill mode
384 jsr VDCWriteByte ; put 1rst byte (fill value)
392 jmp VDCWriteReg ; 1+62*256+127=16000=(640*256)/8
394 ; ------------------------------------------------------------------------
395 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
396 ; The page number is already checked to be valid by the graphics kernel.
398 ; Must set an error code: NO (will only be called if page ok)
409 ; ------------------------------------------------------------------------
410 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
411 ; The page number is already checked to be valid by the graphics kernel.
413 ; Must set an error code: NO (will only be called if page ok)
424 ; ------------------------------------------------------------------------
425 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
426 ; to be in a valid range (0..maxcolor-1).
428 ; Must set an error code: NO (will only be called if color ok)
438 ; ------------------------------------------------------------------------
439 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
440 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
443 ; Must set an error code: YES
448 @L1: lda (ptr1),y ; Copy the palette
449 and #$0F ; Make a valid color
454 ; Get the color entries from the palette
456 ldy PALETTE+1 ; Foreground color
462 ldy PALETTE ; Background color
466 jsr VDCWriteReg ; Clear error code
471 ; ------------------------------------------------------------------------
472 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
473 ; set the palette should return the default palette here, so there's no
474 ; way for this function to fail.
476 ; Must set an error code: NO
484 ; ------------------------------------------------------------------------
485 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
486 ; drivers should return something reasonable here, even drivers that don't
487 ; support palettes, otherwise the caller has no way to determine the colors
488 ; of the (not changeable) palette.
490 ; Must set an error code: NO (all drivers must have a default palette)
498 ; ------------------------------------------------------------------------
499 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
500 ; color. The coordinates passed to this function are never outside the
501 ; visible screen area, so there is no need for clipping inside this function.
503 ; Must set an error code: NO
518 jsr icmp ; if (xres<x1)
519 bcs @cont ; !(xres<x1)
528 jsr icmp ; if (yres<y1)
532 jsr CALC ; Calculate coordinates
554 ; ------------------------------------------------------------------------
555 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
556 ; coordinates passed to this function are never outside the visible screen
557 ; area, so there is no need for clipping inside this function.
561 jsr CALC ; Calculate coordinates
563 stx TEMP ; preserve X
575 @L1: tya ; Get color value into A
576 ldx #$00 ; Clear high byte
579 ; ------------------------------------------------------------------------
580 ; LINE: Draw a line from X1/Y1 to X2/Y2, where X1/Y1 = ptr1/ptr2 and
581 ; X2/Y2 = ptr3/ptr4 using the current drawing color.
583 ; Must set an error code: NO
671 ; for (count=nx;count>0;--count) {
676 @L0166: lda COUNT ; count>0
681 @L0167: jsr SETPIXELCLIP
721 ; if (abs(pb)<abs(ub)) {
737 ; } else { x1 = x1 + ay
776 ; ------------------------------------------------------------------------
777 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
778 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
779 ; Contrary to most other functions, the graphics kernel will sort and clip
780 ; the coordinates before calling the driver, so on entry the following
781 ; conditions are valid:
784 ; (X1 >= 0) && (X1 < XRES)
785 ; (X2 >= 0) && (X2 < XRES)
786 ; (Y1 >= 0) && (Y1 < YRES)
787 ; (Y2 >= 0) && (Y2 < YRES)
789 ; Must set an error code: NO
797 ; Original code for a horizontal line
804 jsr CALC ; get data for LEFT
805 lda BITMASKL,x ; remember left address and bitmask
816 jsr CALC ; get data for RIGHT
820 pla ; recall data for LEFT
823 sta X1 ; put left address into X1
826 cmp #%11111111 ; if left bit <> 0
828 sta TEMP2 ; do left byte only...
843 inc X1 ; ... and proceed
847 ; do right byte (if Y2=0 ++ADDR and skip)
849 cmp #%11111111 ; if right bit <> 7
851 inc ADDR ; right bit = 7 - the next one is the last
856 @L11: lda ADDR ; do right byte only...
871 @L2: ; do the fill in the middle
872 lda ADDR ; calculate offset in full bytes
875 beq @L3 ; if equal - there are no more bytes
878 lda X1 ; setup for the left side
881 lda BITMASK ; get color
882 jsr VDCWriteByte ; put 1st value
885 beq @L3 ; 1 byte already written
887 stx ADDR ; if there are more bytes - fill them...
890 jsr VDCWriteReg ; setup for fill
893 jsr VDCWriteReg ; ... fill them NOW!
900 ; End of horizontal line code
915 ; ------------------------------------------------------------------------
916 ; CIRCLE: Draw a circle around the center X1/Y1 (= ptr1/ptr2) with the
917 ; radius in tmp1 and the current drawing color.
919 ; Must set an error code: NO
925 jmp SETPIXELCLIP ; Plot as a point
943 stx YS+1 ; XS/YS to remember the center
952 @L12: ; plot points in 8 slices...
967 sta Y1+1 ; (stack)=ys+y, y1=(stack)
969 jsr SETPIXELCLIP ; plot(xs+x,ys+y)
977 sta Y1+1 ; y3 = y1 = ys-y
979 jsr SETPIXELCLIP ; plot(xs+x,ys-y)
991 jsr SETPIXELCLIP ; plot (xs-x,ys+y)
996 jsr SETPIXELCLIP ; plot (xs-x,ys-y)
1004 sta X1+1 ; x1 = xs+y
1012 sta Y1+1 ; (stack)=ys+x, y1=(stack)
1014 jsr SETPIXELCLIP ; plot(xs+y,ys+x)
1022 sta Y1+1 ; y3 = y1 = ys-x
1024 jsr SETPIXELCLIP ; plot(xs+y,ys-x)
1028 sta Y1 ; y1 = ys+x(stack)
1036 jsr SETPIXELCLIP ; plot (xs-y,ys+x)
1041 jsr SETPIXELCLIP ; plot (xs-y,ys-x)
1091 @L0148: ; if (abs(ou)<abs(og))
1110 @L014E: ; mo = ou; }
1122 ; ------------------------------------------------------------------------
1123 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
1124 ; direction is passend in X/Y, the text direction is passed in A.
1126 ; Must set an error code: NO
1136 ; ------------------------------------------------------------------------
1137 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
1138 ; current text style. The text to output is given as a zero terminated
1139 ; string with address in ptr3.
1141 ; Must set an error code: NO
1147 ; ------------------------------------------------------------------------
1148 ; Calculate all variables to plot the pixel at X1/Y1.
1149 ;------------------------
1151 ;> ADDR - address of card
1152 ;> X - bit number (X1 & 7)
1166 sta ADDR+1 ; Y*4+Y=Y*5
1176 sta ADDR ; Y*5*16=Y*80
1189 lda ADDR+1 ; ADDR = Y*80+x/8
1201 ; copies of some runtime routines
1219 ; compare a/y to zp,x
1220 sta TEMP ; TEMP/TEMP2 - arg2
1228 tya ; x/a - arg1 (a=high)
1259 @L0: bit VDC_ADDR_REG
1268 @L0: bit VDC_ADDR_REG